1. Technical Field
The present invention relates to a composite heat-dissipation substrate and a method of manufacturing the same. More particularly, the present invention relates to a composite heat-dissipation substrate, which includes a first ceramic layer having insulating properties, a second porous ceramic layer and a metal layer, wherein the first ceramic layer and the second ceramic layer are continuously connected to each other so as not to form an interface therebetween, and the metal layer is infiltrated into plural pores of the second ceramic layer to be coupled to the ceramic layers, whereby interfacial coupling force between the ceramic layers and the metal layer are very high, thereby providing significantly improved heat dissipation characteristics. The present invention also relates to a method of manufacturing the same.
2. Description of the Related Art
Recently, with various merits including high brightness, low power consumption, long lifespan, emission of various colors, eco-friendliness, and the like, light emitting devices (LEDs) have attracted much attention in various fields including backlight units for flat panel displays (FPD), indoor/outdoor lighting, vehicle headlamps, display devices of medical, interior business and electronic communication apparatuses, and the like.
However, regardless of such merits, the LED still has a problem of low heat dissipation due to high junction temperature in an LED module.
High junction temperature in the LED module inevitably leads to high energy consumption and rapid deterioration in luminous efficacy of the LED, thereby causing significant deterioration of reliability.
Thus, in order to solve low heat dissipation of the LED module, various studies have been conducted to develop various types of substrates using metallic materials having high thermal conductivity.
In a conventional heat dissipation structure of the LED module, heat is transferred to a connection part on a circuit board through a heat sink placed within a housing and is then transferred to a metal plate, such as an iron plate, which has good thermal conductivity and is placed under the circuit board, such that the heat can be dissipated to the outside through a wide area of the back side of the metal plate.
Since such a structure employs a metallic material having good thermal conductivity, it is possible to reduce the quantity of heat generated per unit area by allowing heat generated in a region having a high density of LED modules to be rapidly conducted and diffused towards a front side of the metal plate. However, due to difficulty in improving the thermal conductivity of existing highly conductive metal, and limited heat dissipation performance of a lens covering an LED, a heat sink placed under the LED, a sealing package and a coated layer on a circuit board, there are various problems in reduction of the quantity of heat generated per unit area.
To solve such problems, many documents, such as Korean Patent Publication No 10-2008-0079745A and the like, disclose various heat dissipation structures, but do not provide a technique for improving heat dissipation through improvement of interfacial coupling force between a ceramic layer and a metal layer.